It is known in the art to prepare diazocyano acids using a keto acid or a sodium salt of a keto acid as the starting material.
U.S. Pat. Nos. 4,684,717 and 4,684,718 (Ashitaka et al, Aug. 4, 1987) provide a process for the preparation of diazocyano acid, which comprises reacting a keto acid or its sodium salt with a cyanogen compound such as sodium cyanide or hydrogen cyanide and a hydrazine in water to form a concentrated aqueous solution of a hydrazo compound, adding acetone and/or water to the concentrated aqueous solution to form a solution of the hydrazo compound, adding chlorine gas to the solution to oxidize the hydrazo compound and form a diazocyano acid, and separating the diazocyano acid from the obtained reaction mixture.
U.S. Pat. No. 4,831,096 (MacLeay, May 16, 1989) relates to mixtures of azoalkanes of varying thermal stabilities at least one of which is an unsymmetrical azoalkane (R--N.dbd.N--R'). These unsymmetrical azoalkanes are prepared by reacting four equivalents of a mixture of two or more primary alkyl, cycloalkyl or aralkyl amines with one equivalent of sulfuryl chloride in an inert solvent and oxidizing the resulting mixture of sulfamide products with basic bleach. The unsymmetrical azoalkanes can be separate from the symmetrical azoalkanes by a variety of conventional techniques. The azoalkane mixtures are polymerization initiators for vinyl monomers and curing agents for unsaturated polyester resins.